PURPOSE: To improve real transmission efficiency for the amount of data to be really sent out to a transmission line by preparing a real packet only by reloading the pointer of a high-order layer for each layer.

CONSTITUTION: When the data of each layer is equipped with the same processing and the same header, the data of application is divided into packets and the data is transferred while reloading the pointer of the data, which is divided into packets, shown by the same header based on a control table. For example, when an n is defined as a positive integer number, the data 11 in the n th layer is dispatched to the (n-1)th layer while adding the header 12 in the (n-1)th layer and further while adding the header 14 in the (n-2)th layer to the dispatched data, the data is dispatched to the (n-2)th layer 15. Thus, the real transmission efficiency can be improved for the amount of the data to be really sent out to the transmission line.